题解 | #判断是不是完全二叉树#

#coding:utf-8
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param root TreeNode类 
# @return bool布尔型
#
from queue import deque

class Solution:
    def isCompleteTree(self , root ):
        # write code here
        if not root:
            return True
        mark = False
        queue = deque([root])
        while queue:
            top = queue.popleft()
            if mark and (top.left or top.right):
                return False
            if not top.left :
                mark = True
            else:
                queue.append(top.left)
            if mark and top.right:
                return False
            if not top.right:
                mark = True
            else:
                queue.append(top.right)
        return True